The 95mm question

R

Roadhawg

Registered User
The area of a 95mm (3.74 inch) circle comes out to around 11 inches. Does the inlet of the MPX support an inlet area of 11 inches?
Also the inlet plenum will need to be heavily ported on the throttlebody side to support 95mm. It looks like the plenum will need to be ported at the top within ¼ inch of the edge of the casting or less.
 
Seems like recent info shows the mpx plenum is tooo small in general, hows your fab skills, best route IMO is to make a new one, OR hack the current one up and enlarge the whole thing. But I just like hacking stuff up and welding it back together.
 
With known test results, it shows that the 85mm Throttle body actually outflows the MPX inlet plenum at this point by a couple hundred cfm, so while the 95mm would be nice, there's going to be no gains to be had for the MPX folks until a new plenum comes out.

As far as fabbing up goes, I'd love to give it a shot, but I don't have the tooling etc to do it.

Fraser
 
It could be made from sheet metal/steel tubing and mig welded, for the back yard mechainc guys. Some finishing and smoothing work, and some of that nifty epoxy paint Ken Wagner uses, hello FLOW.
 
It would be simple to cut the back section off of the inlet, add a filler piece and weld it back on, BUT..... the hard part is moving the return plenum to make room for the larger inlet plenum.
 
fturner said:
With known test results, it shows that the 85mm Throttle body actually outflows the MPX inlet plenum at this point by a couple hundred cfm, so while the 95mm would be nice, there's going to be no gains to be had for the MPX folks until a new plenum comes out.

As far as fabbing up goes, I'd love to give it a shot, but I don't have the tooling etc to do it.

Fraser
Click to expand...

What about the smiley face on the back of the MPX blower case, does that even have the area of 11 square inches?
 
Roadhawg said:
What about the smiley face on the back of the MPX blower case, does that even have the area of 11 square inches?
Click to expand...

At this point in time I don't know.... I don't have a plenum that I can measure ;).

BUT, I'm sure its at least large enough to support the flow of a 3.5" intake setup which is 9.62 square inches. You also have to remember that even though its a 95mm TB, its not going to flow as much as a 95mm pipe because of the shaft and throttle blade being in the way.

The other thing to keep in mind, ideally you'll want to funnel the flow down to inlet which will accelerate the air going into the blower. Because we are only dealing with atmospheric pressure, we want to try to think of "tuning" the flow into the blower like you would an intake port on a N/A head.

Fraser
 
Roadhawg said:
What about the smiley face on the back of the MPX blower case, does that even have the area of 11 square inches?
Click to expand...

Todd,

I don't think the blower inlet opening cross section needs to be larger than the throttle body cross section to benifit from the reduced inlet restriction of a larger TB and larger inlet plenum.

David
 
neverfastenough said:
It could be made from sheet metal/steel tubing and mig welded, for the back yard mechainc guys. Some finishing and smoothing work, and some of that nifty epoxy paint Ken Wagner uses, hello FLOW.
Click to expand...

Thats actually what I'm considering on doing since I do have a mig that I'm gonna trade for another mig that can do gas.... mine can't.

I also have everything I need to do powder coating so I'm good to go there.

Fraser
 
Don't start cause I know my technical limitations but...

Spent a couple a hrs on this tonight.

We came up with a two piece plenum, winged every 2" except across at the firewall.

CNC work did not look difficult. 2 buckets polish and assemble. We looked at 4X4 AND 4x3. Flange to fit. Not sure of your rear clearances.

Not sure whether I can go any farther. For the TVS we can't come up with a reliable mount without building the manifold and even then all I got was a integrated strap down system (with the hat). Then its the hood- even with the extra clearance on the fibre unit. Snout is less than 4" on the 2300.

Disabling internal bypass is do able either over or under.

Keep the comments coming.

Paul
 
DN

I think your right on.

From what I got tonight it was the reservoir available.

The blower will wick what it needs, its not the speed of the air but volume available.

Paul
 
shoalcracker said:
DN

I think your right on.

From what I got tonight it was the reservoir available.

The blower will wick what it needs, its not the speed of the air but volume available.

Paul
Click to expand...

Thats the problem, if you start letting the blower create a vacuum at its inlet, the temperatures sky rocket at that point, and it will only create so much vacuum before it can't draw anymore, and its not capable of creating alot. When I tested the stock 94 plenum on a 94 blower, I found that the temperatures started sky rocketing with over 10% OD on it. Once I put the MP plenum on the blower (this blower was very well ported) I was able to get more CFM out of the blower and the temperatures stayed down until after 15% OD.

I am seeing the exact same thing with the MPX blower and its plenum. At 15% OD, I can take the motor right up to 6000 and the drop starts there and becomes noticable at 6200, and the temps start to climb at that point. Go to 25% OD and you'll see the same thing only starting at about 5200.... This falls into line with flow bench testing that Dave Dalke did with these parts.

You can't depend on the blower to get, or wick what it wants, hence the reason for the big CAI systems required, since those rotors will only fill with atmospheric pressure. Any kind of vacuum on the inlet side and the blower's VE goes down hill very quickly. This is the reason I am suggestion trying to increase the velocity of the air as it travels to the blower, just like cylinder filling when the intake valve opens on an N/A motor, you start with a large opening and narrow it down to the back of the valve to accelerate the air going in.

Volume is important, and accelerating that volume to the blower will also help fill the rotors at high rpm's, which is where the MPX shines. It would be detrimental to start with a smaller MAF, got to a 95mm TB then go back down to a small inlet plenum, as the turbulence would slow flow down considerably, and you could have less flow than sticking with an 85mm TB on that setup.

Fraser
 
Fraser

I do not have access to this kind of data or the knowledge to interpret...

If I build, and thats debatable right now I will lean towards..

Residual volume, rotor design, and air pump efficiency.

I know the components available, just haven't been able to get them to talk to each other yet.

Paul
 
fturner said:
Thats the problem, if you start letting the blower create a vacuum at its inlet, the temperatures sky rocket at that point,
Click to expand...

So does the inlet on the MPX blower case have the abilitiy to flow what a 95mm throttlebody is capable of?
Will the choke point be the back of the blower case if everything upstream is properly sized to utillize a 95mm throttlebody?
 
shoalcracker said:
For the TVS we can't come up with a reliable mount without building the manifold and even then all I got was a integrated strap down system (with the hat). Then its the hood- even with the extra clearance on the fibre unit. Snout is less than 4" on the 2300.

Disabling internal bypass is do able either over or under.

Keep the comments coming.

Paul
Click to expand...

So I assume you have a TVS blower and are installing it in A SC? I am really interested in that. You should post a thread about it if you havent already have

Ken
 
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